CN1038086A - The method for oxidizing hydrocarbons that utilizes oxidizing gas to distribute - Google Patents

Abstract

Disclosed a kind of sequential portion method for oxidation of hydrocarbon, wherein will in the container that separates, distribute to hydrocarbon with reflux type by the aqueous solution of prepared oxygen, thereby avoid hydrocarbon directly to contact with oxidizing gas.

Description

The method for oxidizing hydrocarbons that utilizes oxidizing gas to distribute

The present invention relates to a kind of improved hydro carbons controlled oxidation method.More specifically say, the present invention relates to from an aqueous solution, to distribute oxygen and enter in the hydrocarbon of preparing oxidation, and from through the hydrocarbon of oxidation, reclaiming excessive oxygen.

The controlled oxidation of this hydro carbons controlled oxidation, particularly aliphatic series and cycloaliphatic hydrocarbon is a kind of essential industry method, in order to prepare multiple oxygen containing organic compound, comprises alcohols, aldehydes, ketone and carboxylic-acid or the like.For example, utilize hexanaphthene to make multiple product by partial oxidation, comprise hexalin, pimelinketone, hexanodioic acid, Alpha-hydroxy caproic acid for raw material.These products can be used as the intermediate of preparation multiple product such as hexylene glycol and hexanolactam etc. then.

Other are usually used in oxidation and make the hydro carbons of OXO products and comprise butane, hexane, hexanaphthene, benzene, naphthalene.Can say equitably, produce the product that accounts for significant proportion on the organic chemicals commodity market by the oxidizing process process that comprises these hydrocarbon and other hydrocarbon.

Disadvantageously, these exist serious safety problem in the hydro carbons controlled oxidation process that high temperature carries out usually.In the flammable liquid of any heat, directly feed oxygen, comprise the oxygen in pure oxygen, the atmosphere or the air of oxygen enrichment, the danger of fire and blast all can be arranged.When carrying out vapor phase oxidation or used equipment can make reactor gather oxygen containing hydrocarbon steam the time, especially dangerous by the top.Under latter event, with pure oxygen than more dangerous with air because their limits of explosion will be wideer many.Because very unsettled superoxide and hydroperoxide usually account for the suitable vast scale of this class oxidation products, have further increased the weight of this class technological process inherent danger.

In conventional formula oxidation, be air is passed to reactor bottom and to be small bubbles and to send into, and want the monitor closely reactor head space whether to have unreacted oxygen.In European patent application EP-A-0199339, used pure oxygen, and fed in the lower aqueous layer by means of oxygen being disperseed very thin, avoided oxygen initially to contact with the direct of hydrocarbon.The hydrocarbon of preparing deoxidation is the oxygen dissolution vessel that feeds this aqueous phase layer top.Yet this method has such shortcoming, though prevent that by means of the pure oxygen of careful control block contacts with the initial of hydrocarbon, still has the oxygen of physical entity in this dissolution vessel, therefore exists the big dangerous of blast.

Have found that,, the aqueous solution of oxygen is contacted with this liquid hydrocarbon make the oxygen distribution and enter in the hydrocarbon of wanting oxidation, can avoid like this in this oxidizing gas feeding hydrocarbon by means of earlier oxidizing gas (for example oxygen) being dissolved in water in another container.Under such condition, oxygen is under controlled condition, that is does not exist in fact under the condition of gaseous oxygen and be delivered in the hydrocarbon, and the security of whole oxidizing process process is improved greatly.

Fig. 1 is a cover lab setup, in order to show that oxygen is delivered in the liquid hydrocarbon from the aqueous solution of oxygen.Fig. 2 is the technical process that liquid hydrocarbon is oxidized into oxidation products, and what wherein take is the method that oxidizing gas is distributed between the hydrocarbon of water and preparation oxidation.In addition, Fig. 2 has also described will to consume the method that the remaining excess of oxygen in back is removed in the oxidising process by reverse distribution.

The oxidation of hydrocarbon is that the people knows and in the method for industrial widespread use.Type, catalyst system therefor and other details: the Berezin etc. of oxidising process, hydrocarbon base material have been described in the following document, The Oxidation of Cyclohexane, Pergamon Press, New York,

1966; Emanuel etc., The Oxidation of Hydrocarbons in the Liquid Phase, Pergamon Press, the MacMilan Co., New York,

1965; Some United States Patent (USP)s: USP 4,322,558; 3,933,930; 3,923,895; 3,937,735; 3,991,099; 3,681,447; 3,719,706; 3,761,517; 3,869,508; 3,965,164; 4,227,021; 4,263,453; 3,671,588; 3,932,513; 3,948,992; 3,987,115; 4,055,600; 4,098,817; 4,341,907; 3,946,077.

In the method for the invention, the solution of preparation oxygen in water preferably adopts the continous way operation earlier.Then, distribute or equivalent with it method, be preferably in room temperature or be lower than room temperature, oxygen is transferred in the hydrocarbon of preparing oxidation by means of adverse current.The hydrocarbon that will contain dissolved oxygen then is heated to the oxidizing temperature of requirement, and transfers in the reaction vessel.After the reaction, product is separated with unreacting hydrocarbon, with latter's recirculation.Preferably the water major part that is used to provide requisite oxygen is also gone recirculation.

By method of the present invention, be that air, oxygen-rich air or oxygen are dissolved in the water under pressure, make the aqueous solution of oxygen, used pressure should be can be enough to be dissolved into required oxygen amount in used technological process temperature.The people knows, and the solubleness of a kind of gas in a kind of liquid is that the tranquil difficulty of the vexed  of Jiao is bought Τ and burnt  and get the abundant of K  and consult when buying ξ 0 crust haply, and the solubleness of oxygen in water approximately is 10 times when pressure 1 crust.So from the Handbook of Inorganic Chemistry of Gmelin, p.461 " Sauerstoff, " 3d Ed. learns, oxygen is approximately 0.04 grams per liter at 1 crust and 25 ℃ solubleness.At 10 bar pressures, its solubleness will be about 0.4 grams per liter, and at 100 bar pressures, solubleness will be about 4 grams per liters.

Along with temperature raises, the solubleness of oxygen in water descends.So at 50 ℃, the solubleness of the solubleness of oxygen than 25 ℃ descends about 30% under condition of normal pressure.So when to oxygen in water, no matter these oxygen are from air, oxygen-rich air or pure oxygen, temperature must remain on low as far as possible.So the temperature of water can remain on envrionment temperature, better be to be lower than 70 ℃, be more preferably 25 ℃ or lower.In the following description, the oxygen of oxygen, oxygen-rich air in the oxygen, air than pure state will be represented in this noun of oxygen, perhaps contain oxygen and one or more and under these processing condition be the oxygen in the gas mixture of inert gasses.

For the oxygen (approximately 2-10%(weight) that preferred amounts can be provided in this hydrocarbon), the dividing potential drop of oxygen should be about 5-200 crust, better is about 5-100 crust, preferably about 7-60 crust.Required pressure is easy to calculate, and perhaps processing parameter in accordance with regulations (as the highest design operation pressure and the desired operating restraint of equipment used) is determined by experiment.The pressure of oxygen will depend on that the concentration of desired oxygen in hydrocarbon, water are to the relative quantity of hydrocarbon, the hop count and the equilibrium relationship of oxygen between water and hydrocarbon of pass segment.According to the distribution system of four theoretical sections, and the volumetric flow rate of water is 7.2 times of examples to the hexanaphthene flow, be provided to contain the 5%(mole in the hexanaphthene approximately) oxygen, the about 830 pounds/square inch gauge of required dividing potential drop.The table I shown under other operational conditions required pressure.

The dissolution process of oxygen in water can be finished with any method that makes things convenient for.For example, the drum in storing in pressure-pot is gone into oxygen bubble.Little mode can feed oxygen, and water is fed this top of tower, or water is sprayed in the tower that is filled with oxygen at the bottom of the tower of a tower, particularly packing tower in addition.By means of this kind adverse current dissolution process, make a large amount of use oxygen and water become economically feasible.Those skilled in the art can also propose the mode of other dissolved oxygens.

The water that is used for dissolved oxygen can be fresh water, can be recirculated water, and perhaps both mix use.Preferably with most of water cycle.Can contain dissolved solids or organism in the water, as long as they do not have unfavorable effect to the dissolving and the later oxidizing reaction of oxygen.Recirculated water also can derive from the reverse partition liquid stream of fresh or recirculated water, and be that the product that is used for after the oxidation removes unreacted oxygen anti-the distribution.

Alkaline matter, particularly strong alkaline substance should have been avoided, as alkali metal hydroxide, because known these materials can make the oxidizing reaction of hydrocarbon slow down.In addition, strong alkaline aqueous solution can make the transition metal precipitation, is settled out the oxide compound of their oxide compound, oxyhydroxide or hydration, therefore not only can make them lose catalytic activity, the also potential problem that occurs dirt.

Should avoid using the aqueous solution that contains more amount dissolved inorganic salt,, the solubleness of oxygen in this solution be descended because when these salt have higher concentration.If the long period has been gathered these materials in the recirculated water in this technological process, just must increase a segregation section removes these materials, and regulates the round-robin water yield, or is regularly to use fresh water as the water source technological process to be restarted.

Preferably used water is neutrality or subacidity, and can contain the specific oxide catalyst of significant quantity when needed.These oxide catalysts have been known in the present technique field, generally are the salt or the complex salt, particularly transition metal of metal or the salt of heavy metal, as cobalt, chromium, manganese, vanadium, aluminium, lead, tin, copper.At the preceding many examples that can find this type of catalyzer in the reference that draw.Be water miscible, have the water-soluble of a certain degree at least owing to have many in these catalyzer, so be used to provide the same a collection of water of oxygen also can be used for supplying with catalyzer to hydrocarbon.

Oxygen is to finish by the contact of two kinds of liquid from the distributional effects of the aqueous solution to the hydrocarbon of preparing oxidation of oxygen, preferably adopts such method, even the surface-area of liquid-liquid interface strengthens as far as possible.Be preferably in room temperature or be lower than room temperature and in the packing tower of adverse current, make two kinds of liquid contacts.Because the solubleness of oxygen in hydrocarbon is generally higher, can be passed to nonaqueous phase to quite a large amount of oxygen from water at an easy rate, and transmit to reach degree be being the limit at the partition ratio of this contact temperature oxygen in these two kinds of liquid.In addition, by means of the much bigger water of recycle ratio hexanaphthene amount, oxygen concn can be increased to above the concentration in the water in the hydrocarbon." quite a large amount of " used herein but a speech is meant sizable mark of transmission capacity in theory, promptly at least 10%.

After being assigned to oxygen in the hydrocarbon phase, hydrocarbon is heated to desired oxidizing temperature.When having used catalyzer in oxidation, they can add before or after arriving desired reaction temperature, perhaps as top proposition, can be assigned to the hydrocarbon from water.Institute of the present invention safety factors of inherent just is, oxygen is in many hydrocarbon, and particularly the solubleness in hexanaphthene does not resemble its solubleness in water but along with temperature rises and solubleness is strengthened.Therefore, the solubleness of oxygen in hexanaphthene is respectively 12.3,12.4 and 12.7(* 10 at 283.5 ° of K, 297.6 ° of K and 313.1 ° of K under condition of normal pressure ^-4) the %(mole).Additional safety factors so just is provided, because the saturated solution of an oxygen in hydrocarbon becomes unsaturatedly after temperature raises when room temperature, so oxygen forms gas phase with regard to unlikely effusion.

Oxidizing process process itself is conventional formula fully.After the oxidation, separated product is also with it purification in a usual manner.

The hydro carbons that is applicable to the inventive method comprises benzene, toluene and other lightweight aromatic hydrocarbon, but particularly suitable is aliphatic hydrocrbon, as butane, pentane, hexane, octane-iso or the like, optimal is cycloalphatic hydrocarbon, as pentamethylene, cyclopentenes, cyclopentanol, hexanaphthene, tetrahydrobenzene, hexalin, methylcyclohexane, dimethyl cyclohexane, optimal is hexanaphthene.

By accompanying drawing and with reference to example the present invention is set forth.But these contents are not limiting the scope of the invention.Those skilled in the art can propose multiple available to this claimed technological process by themselves and change scheme.All these variation schemes all are to belong within the scope of the present invention.

Example 1

Determine oxygen is assigned to feasibility in a kind of hydrocarbon from the aqueous solution by following experiment.With reference to Fig. 1, hexanaphthene is sent into container F ₁In and purged 12 hours with nitrogen, need the complete Ex-all of dissolved oxygen with him.Trap T is caught in utilization ₁The hexanaphthene steam of discharging in the nitrogen is removed and makes it to flow back to this container.To container F ₂In send into distilled water and with air purge 12 hours, made the oxygen in the atmosphere wherein saturated.Pressure all is not higher than normal pressure, the back pressure slightly that just has instrument itself to produce.

In each operating process, use pump P ₁With container F ₂In water pump deliver to storage vessel A, from A again by valve V ₁And send into distributing tower C ₁The top.Distributing tower C ₁Be a no filler glass tower, 25.0 centimetres of length, about 0.9 centimetre of internal diameter.Meanwhile, use pump P ₂Hexanaphthene is pumped and process valve V ₂And the hexanaphthene of sending into distributing tower enters the mouth.The hexanaphthene that contains dissolved oxygen is at overflow device D ₁This tower is left at the place.Water is to enter this tower through one section 1/8 inch vertical pipe, falls and passes the hexanaphthene layer with the water droplet form, but do not touch Ta Bi, passes through valve V then ₃Leave this tower and enter storage vessel B, pass through overflow device D then ₂Overlap instrument and leave this.The interface liquid level of water/hexanaphthene is by regulating D ₂Height regulate.Regularly measure the flow of hexanaphthene and water.Gas-phase space among container A and the B remains on inferior limit.The steam of all classifications is all from tower C ₁In carefully remove.Contain water in the container C, the oxygen of all discharges all flows through it.E is emptying among the figure, and f is a hexanaphthene, and g is a purging air, and h is for purging N ₂, i is an air, and j is for being communicated to atmosphere, and k is a water.In required time, measure the water oxygen level of container A and B, use 501 type Orion Digital Ionalzer during mensuration, use the Orion O of model 970800 ₂Electrode.All this electrode is demarcated again before each the mensuration.The data of operating gained for several times shown in the table I.

Can see from example 1, even in condition of normal pressure, the about 26-31% of the oxygen in the aqueous solution can be assigned in the hexanaphthene.It should be noted that lower, the unloaded tower of usefulness is just used in such distribution, duration of contact is also very short to be reached.Use the expection of packing tower or buffle-type tower can increase transmission capacity.

Shown in Figure 2 is the schema of extensive hydrocarbon oxidation (for example cyclohexane oxidation).The equipment material therefor is conventional formula, and is that the present technique field is known.Generally speaking, preferably use stainless steel, clad metal or lining glass equipment, make corrosion reduce to minimum.Owing to adopted high pressure, wished that each tower adopts big length, especially tower C ₁And C ₂, can reduce diameter so as far as possible, thereby can utilize structured material economically and bigger safety coefficient is provided.All towers comprise reactor R ₁Generally all be filled with conventional formula filler, for example spherical, saddle, spirrillum filler etc., however plate tower and no packing tower are operable theoretically.

When operation, the water that pressurizes is passed through valve V ₆Send into oxygen dissolving tower C ₁The top.These water can be by pipeline L ₂With valve V ₂And the fresh water that comes, or be all or part of recirculated water of using as described later.With pure oxygen, be the oxygen that dilutes of inert gasses under these processing condition, with the oxygen or the pump P of the oxygen in the atmosphere of air dilution ₁Pressurization is also passed through valve V ₁And send into tower C ₁The pressure of oxygen and flow all can be regulated, so that dissolve desirable oxygen %(mole in water).

The water that contains aerobic is by pipeline L ₄Emit from this tower, by pump P ₂And enter distributing tower C ₂Liquid hydrocarbon pump P ₃Pressurization and process valve V ₈And send into tower C ₂Because proportion differs, and sets up reverse flow conditions in the tower, lighter oxygen-containing hydrocarbon is from pipeline L ₈Leave this tower, and the water that loses oxygen is by hydrocarbon/water termination I ₁Following pipeline L ₅And emit.For the hydrocarbon situation heavier than water, the turnover position of each streams all will reverse.For being the solid hydrocarbon in room temperature, then this tower should be heated to that to be enough to keep this kind hydrocarbon be the temperature of liquid.

Rich oxygen containing hydrocarbon can be from pipeline L ₈Enter next distributing tower so that further increase oxygen level, or press shown in the figure at tower C ₃In outgas.An important requirement of present method is exactly that native system will remain under enough pressure conditions, makes oxygen all be in the solution and does not form gas phase.Reason advises making tower C for this reason ₂The a little higher than tower C of pressure ₁Pressure.Simultaneously, must consider that also the pressure that produces falls in process pipeline.Needing most the requirement that reaches is not because the pressure that must take place falls and outgassing takes place, so tower C ₃It is an extra security measures.The gas of all recovery can be discharged in the atmosphere, drains into torch and burns or the most handy pump P ₄Compression back and siphunculus road L ₉Dissolve tower C and be recycled to ₁The hydrocarbon of oxygen enrichment oxygen is through metering and by valve V ₁₀And send into reactor R ₁Reactor R ₁Suitable oxidizing temperature operation, for example 100-200 ℃.Use heat exchanger H to provide initiation reaction required heat, and can take heat away by the more heats of needs supply of technological process or from reactor.

This oxidizing reaction promotes that by adding suitable catalyzer add-on is about 0.01-100ppm usually.Because the handiness that native system had can add catalyzer from one or more positions.For example, can pass through pipeline S ₁With valve V ₄Add tower C ₁The water inlet place, adding fashionable can be a kind of aqueous solution, or is dissolved in the appropriate solvent.Preferably used solvent is exactly one of product of this reaction.When oxidation be hexanaphthene the time, used solvent can be hexalin, pimelinketone or these mixture of products.Other mode can add catalyzer at oxygen before distributing between water and the hydrocarbon, can pass through pipeline S ₂With valve V ₇And filling line L ₄; Or before oxidation, add, can pass through pipeline S ₃With valve V ₁₁Filling line L ₁₀

Generally contain the 1-15%(weight of having an appointment in hydrocarbon liquid after the oxidation stream) oxidation products, more common is to contain about 3-8%.Processing through oxygenated hydrocarbon can have multiple mode.For example, from R ₁Out-feed liquid stream L ₁₁Can react with caustic alkali, or come decompose hydroperoxide and hydroperoxide, send into tower C then with other proper methods ₄Other mode, this oxidation products can carry out fractionation before or after peroxide breakdown.For example the situation of cyclohexane oxidation contains pimelinketone and hexalin in the high boiling fraction, and both all have certain solubility in water, so herein just can be with being sent to tower C ₄Streams in unclassified stores (major part is a hexanaphthene) be separated.

Also having a kind of mode is with tower C ₄And C ₅Bypass fully, and process from R with usual manner ₁Effusive oxidation products.But the present invention has uncommon supplementary features, is exactly can be at tower C ₄In, or as shown at C ₄And C ₅The middle utilization " oppositely distributed " and removed all remaining unreacted oxygen that get off, thereby makes R ₁Toward being issued to greater security.

Fresh water can pass through valve V ₁₂Enter tower C ₅, for example by pipeline L ₁₂Send and enter tower C ₄, at last by pipeline L ₃And from tower C ₄Come out.Other mode can add fresh water in two towers, and the both sends from each tower bottom or bottom being bordering on.

So pipeline L ₃In water in except that saturated hydrocarbon, dissolved oxidation products (mainly being monobasic and binary organic acid) and contained the catalyzer, also contain the oxygen of minimal amounts of dissolved.These water can pass through valve V ₅Be recycled to tower C ₁, can account for the 10-25% of the water yield in the system or more therein.Enter valve V by each fresh water ₂And V ₁₂Suitable equilibrium, then should be able between each system component concentration in the water liquid stream, reach balance rapidly in this system.Might be regularly or emit a part of water liquid stream continuously (for example from pipeline L ₄Or L ₅Emit) and adjust institute relief liquor stream and make these deoxidations and be substantially free of the current direction tower C of hydrocarbon ₄Or C ₅Other mode, the water that is used to remove unreacted oxygen can be by means of reducing pressure at tower C ₆Within the degassing, then as by pipeline L ₁₄Molten organic acid source of supply.

Claims (19)

1, a kind of hydrocarbon partial oxidation is made the method for the product that contains the hydrocarbon oxidation products, wherein uses molecular oxygen, after improving, may further comprise the steps as oxygenant:

A) aqueous solution of preparation oxygen in the container that separates;

B) aqueous solution with described oxygen contacts with the liquid hydrocarbon of preparing oxidation, and its way of contact is to make the oxygen of volume be passed to this hydrocarbon phase from this water;

C) in high temperature described oxygen containing hydrocarbon is carried out oxidation then.

2, the process of claim 1 wherein that the preparation of the described aqueous solution is in about 5-200 bar pressure oxygen to be dissolved in the water.

3, the process of claim 1 wherein that the transmission of described oxygen is to carry out in the tower of counter-current condition.

4, the method for claim 2, the transmission of wherein said oxygen are to carry out in the tower of counter-current condition.

5, the process of claim 1 wherein that the water that has removed oxygen in step (b) is to be recycled in the step (a).

6, the method for claim 2, the water that has wherein removed oxygen in step (b) is to be recycled in the step (a).

7, the method for claim 3, the water that has wherein removed oxygen in step (b) is to be recycled in the step (a).

8, the method for claim 4, the water that has wherein removed oxygen in step (b) is to be recycled in the step (a).

9, the process of claim 1 wherein that step (b) is to carry out in envrionment temperature.

10, the method for claim 4, wherein step (b) is to carry out in envrionment temperature.

11, the process of claim 1 wherein that step (b) is to carry out in the temperature that is higher than step (a).

12, a kind of hydrocarbon partial oxidation is made the method for the product that contains the hydrocarbon oxidation products, wherein uses molecular oxygen, after improving, may further comprise the steps as oxygenant:

A) aqueous solution of preparation oxygen in the container that separates;

B) aqueous solution with described oxygen contacts with the liquid hydrocarbon of preparing oxidation, and its way of contact is to make the oxygen of volume be passed to this hydrocarbon phase from this water;

C) in high temperature described oxygen containing hydrocarbon is carried out oxidation then.

D), from described product, remove all unreacted oxygen by means of between (c) step products and water, distributing oxygen with reflux type.

13, the method for claim 12, wherein the water described in the step (d) is fresh water.

14, the method for claim 12, wherein the water described in the step (d) is the technological process water of taking off oxygen.

15, the method for claim 12, wherein the heavy-oxygen-enriched water that produces in step (d) is to be recycled to step (a).

16, the method for claim 13, wherein the heavy-oxygen-enriched water that produces in step (d) is to be recycled to step (a).

17, the method for claim 14, wherein the heavy-oxygen-enriched water that produces in step (d) is to be recycled to step (a).

18, the method for claim 12, wherein contained superoxide and hydroperoxide are with it decomposition remove unreacted oxygen with step (d) before in step (c) product.

19, the method for claim 12, wherein contained superoxide and hydroperoxide are decomposed in step (c) product, and with gained mixture fractionation becoming hydrocarbon and hydrocarbon oxidation products cut, and be that (d) handles set by step with this hydrocarbon-fraction only.

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